Elevator control system



Nov. 12, 1935. H. w. WILLIAMS ELEVATOR CONTROL SYSTEM Filed'Jan. 2, 1935 5 Sheets-Sheet 1 INVENTOR Nov. 12, 1935. H. w. WILLIAMS 2,020,931

ELEVATOR CONTROL SYSTEM 5 Sheets-Sheet 2 Filed Jan. 2, 1935 r as/ 51 7* W CPTZ aur4 cuT/ L [:ZE w?- un (urz JAM IN NTO f/ara/a M 1407067075.

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ATTO EY Nov. 12, 1935. H. w. WILLIAMS ELEVATOR CONTROL SYSTEM 5 Shets-Sheet 5 Filed'Jan. 2, 1935 Sbm INVENTOR 9 EVAN VJMUSM '9 m m w M SQN /E SQ WITNESSES:

1 A QWEQV Patented Nov. 12,1935

UNITED STATES PATENT OFFICE ELEVATOR CONTROL SYSTEM Application January 2, 1935, Serial No. 65

25 Claims.

My invention relates, generally, to electrical control systems and it has particular relation to control systems for elevator cars.

The object of my invention, generally stated, is to provide a control system for elevator cars which shall be simple and eflicient in operation and which may be readily and economically manufactured and installed.

An important object of my invention is to provide for limiting the number of calls effective for stopping an elevator car.

Another important object of my invention is to provide for limiting the number of calls effective for stopping an elevator car to those calls registered before the car leaves a terminal in the direction for which the call is registered.

Another object of my invention is to provide for indicating at a floor, the car which has been assigned to answer a call registered at the floor.

A further object of my invention is to provide for preventing the re-registration of a call at a floor until the previously registered call has been cancelled by the stopping of a car at the floor.

Still another object of my invention is to provide a control system for accomplishing the control functions set forth in the foregoing objects.

Other objects of my invention will in part be obvious, and in part appear hereinafter.

My invention, accordingly, is disclosed in the embodiment shown in the accompanying drawings and comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the application of which will be indicated in the appended claims.

For a more complete understanding of the nature and the scope of my invention, reference may be had to the following detailed description taken in connection with the accompanying drawings, in which Figure 1 schematically illustrates the arrangement of two elevator cars in an elevator bank, together with certain associated equipment;

Fig. 2 illustrates diagrammatically the condition of the floor selector when the car individual thereto has stopped at the third floor;

Figs. 3 and 4 illustrate diagrammatically a control system organized in accordance with my invention, and

Figs. 5 and 6 illustrate the contact arrangement and operating windings for the various relays illustrated in Figs. 3 and 4.

It is intended that Fig. 3 shall be positioned above Fig. 4, and that Fig. 5 shall be positioned above Fig. 6, in order to clearly interpret the drawings. When Figs. 5 and 6 are positioned, respectively, alongside of Figs. 3 and 4, it will be noted that the contact members and operating windings of the various relays are substantially 5 in horizontal alignment.

According to my invention, two or more elevator cars are provided in a bank of elevators. Any suitable control system may be used for controlling the motor which serves to raise and lower the 10 elevator cars in their respective shafts. It will also be understood that any suitable dispatching system, well known to thom skilled in the art, may be used for properly scheduling the cars, so that they may leave the terminals at spaced 15 intervals.

In order to speed up the service which is rendered by the cars to the various floors, it is desirable to limit the number of calls which are effective for stopping each car in its movement 20 between the terminals. Ordinarily the car nearest to the floor where a call is registered is the car which is stopped to answer the call. With such an arrangement, it is quite likely that the service to the various floors will be unsatis- 5 factory and there is a possibility that some cars will be overcrowded while others will be travelling with few or no passengers.

With a view to providing for rendering more uniform service, I have provided a control sys- 3o tern for an elevator bank in which the number of calls that are effective for stopping any particular car is limited to the calls which are registered before the car leaves a terminal in the direction for which-the calls are registered. Thus, all 35 of the registered calls are assigned to the car next to leave a terminal and the calls subsequently registered are assigned to the next car to leave.

It will then be understood that no calls are effective to stop a car once it has left a terminal, except 4 those calls which were registered before the car left the terminal.

In order to provide for registering calls, up and down call buttons are provided on each floor in the customary manner. Associated with each 45 call button is a master relay which is arranged to be energized on operation of the corresponding call buttonv As soon as the master relay is operated, a holding circuit is completed which serves to maintain the master relay energized after the call button is released.

Each of the elevator cars is provided with up and down floor relays, each relay corresponding to the master up and down relay which is individual to each floor. As soon as a floor relay is operated, it effects the deenergization of the corres onding master relay and prevents its subset reen rgization until the call has been cancel ed by the arrival of the car at the floor wh re call is registered.

Each car is also provided with a zoning relay which is in lvidual to each terminal. As soon as a car arrives at a terminal, the zoning relay individual thereto is energized and is effective to transfer all of the calls which have previously been registered for the direction in which the elevatcr car will next travel to the floor relays individual to the car.

In order to indicate to the person operating the call button at any floor which car will stop at the floor, each elevator is provided with a pair of hall lanterns on each floor, one for each direction or travel. As soon as a call has been assigned to a particular car, the hall lantern individual thereto will be illuminated to indicate, in advance, which car will stop at the floor. The person calling the elevator can then wait at the door of the particular car which will answer the call with the assurance that it is the one which will answer the call and no other car. It is, therefore, possible to speed up the operation of the system, in view of the fact that ordinarily passengers will be in front of the door of the elevator which is to answer the call when it arrives at the floor.

The car to which a call is assigned, on approaching the floor where the call is registered, may be automatically slowed down and stopped by any suitable motor control system. For purposes of illustration, a particular motor control system has been illustrated in the drawings, but it will be understood that other control systems may be employed without departing from the scope of the invention.

As the car leaves a floor after having been stopped. at the floor in response to the registration of a call, the corresponding floor relay is restored to the non-operated position. The restoration. or the floor relay is effective to extinguish the hall lantern which had previously been illuminated, and also is effective to condition the energizing circuit of the corresponding master relay, so that a call at that floor may again be registered.

It will then be understood that a call is registered and held, if no car is at a terminal from which it can proceed. in a direction for which the call is 'egistered. As soon as a car arrives at a l and is next to leave, the registered calls will l ned to it as well as all calls which are registered while the car is at the terminal. No call can be ren'egistered until the original call has been answered. The hall lantern at the floor w ere a call originates is illuminated as soon as he call has been assigned to a particular and remains illuminated until the car leaves that floor.

In illustrating and describing my invention, elevator cars A and B have been shown. In order to redu the n mber or reference characters, the

' is common to both cars. and the is individual to car A has been reference characters. Since cters are applied to the ap- B with the prefix B. of the for supporting car A in its over sheave 2 and is connected erweight 3, in the customary manparicularly to Fig. l

ner, for balancing the weight of the car A. The sheave2 is driven by means of a motor M, which is provided with a brake 4 and a brake release winding 5 for stopping the car A when the motor M is deenergized.

In order to effect the stopping of the car A at the various floors, a floor selector, illustrated generally at 6, is provided. A shaft 1, which is driven by the motor M, is arranged to operate lead screw 8 for moving a brush carriage 9, Fig. 2, in correspondence with the movement of the car A in the shaft.

As illustrated in Fig. 2 of the drawings, the brush carriage 9 is provided with call pick-up brushes XU and XD, which are arranged, respectively, to engage call pick-up segments 25, 24-, 44 and 22, 32, 42. In like manner the brush carriage 9 is provided with call cancelling brushes YU and YD, which are arranged, respectively, to engage call cancelling segments 43 and Z l, 3 I, 4 I. The brush carriage 9 is 21.510 provided wi auxiliary brushes H and 5|, which are arranged, respectively, to engage auxiliary ficor segments l0 and 50.

It will be observed that auxiliary segment I0 is associated with the first floor, that segments 2| through 24 are associated with the second floor, segments 3| through 34 are associated with the third floor, segments 4| through 44 are associated with the fourth floor and segment 50 is associated with the fifth floor. In the event that additional floors are to be served, it is only necessary to provide additional intermediate floor segments similar to those provided for the floors intermediate the terminal floors, as illustrated.

Floor segments 23, 24, 33, 34, 43 and 44 are associated with the up direction of travel of the brush carriage 9 while the remaining corresponding floor segments are associated with the down direction of movement of the brush carriage. It will be understood that when the lead. screw 8 is rotated in a direction corresponding to the movement of the car A upwardly, the brush carriage 9 is rotated slightly so that the brushes XU, YU and 5| will engage their corresponding floor segments. In like manner, when the lead screw 8 is rotated in a reverse direction, the brush carriage 9 is rotated slightly so that brushes XU, YU and 5| will no longer engage their corresponding floor segments and that brushes XD, YD and II will engage their corresponding floor segments. It will be understood that other types of floor selectors may be used in practicing my invention, and, therefore, it is intended that the floor selector shown is for illustrative purposes only.

The elevator car A is provided with a master switch MS for manipulation by the operator to initiate the movement of the car in either direction, and also to cause it to stop at a floor in order to discharge passengers for any of the floors which they have requested. As shown, the master switch is arranged to be positioned in three different positions corresponding to movement in either an up or a down direction, and in a position for effecting the stopping of the car.

In order to stop the car at a floor where a call is registered, a slow down inductor switch E and a stopping inductor switch F, carried by the car A, are provided. These inductor switches may be constructed in accordance with the teachings of Patent No. 1,902,602, issued March 21, 1933. to Williams et a1. and assigned to the assignee of this application.

The slow down inductor switch E is provided with normally closed contact members El and E2.

When the operating winding of the inductor switch is energized, no operation takes place until the contact members El or E2 are in proximity to inductor plates E'V and ED respectively. Thus, when the car A is approaching the third floor in the up direction and the operating winding of the inductor switch E is energized, contact members El will be opened as soon as they are in proximity to the inductor plate E'V. In like manner, when the car A is moving downwardly, contact members E2 will be opened when they are in proximity to the inductor plate ED. As long as the operating winding of the inductor switch remains energized, the contact members will remain in the open position once they have been operated to that position.

In like manner, stopping inductor switch F is provided with contact members FI and F2 which are arranged to be moved into proximity with inductor plates FU and FD respectively. The inductor switch F is effective for stopping the car at the floor where a call has been registered.

In order to provide for registering a call to stop an elevator car at any particular floor, the third floor for instance, call buttons 3U and 3D are provided. Since it is desirable that the person operating a call button be informed as to the car which will answer the call, hall lanterns 3UL and 3DL are provided. It will be observed that corresponding call buttons and hall lanterns are provided for the other floors, as is shown in the diagram illustrated in Fig. 4 of the drawings.

While only two elevator cars have been illustrated in order to point out the novel features of my invention, and these two cars are shown as operating between the first and the fifth floor, it will be understood that a greater number of cars may be used and that they may be arranged to serve a greater number of floors. In the control system to be described hereinafter, provision is made for certain of the connections which would be used for a third car C, in order to illustrate how the system may be expanded to accommodate a larger number of cars. It will, however, be obvious to those skilled in the art how the system may be employed for a larger number of cars and for serving a greater number of floors.

Referring now particularly to Fig. 4 of the drawings, it will be observed that call buttons 2U, 3U and 4U are illustrated and may be operated to effect the stopping of a car at the corresponding fioor for travel in the up direction. In like manner, call buttons 2D, 3D and 4D are provided individual to each floor for registering calls for traflic in the down direction. Master relays 2UM, 3UM and 4UM are provided individual to the corresponding call buttons 2U, 3U and All. In like manner, master relays ZDM, 3DM and 4DM are provided individual to the corresponding call buttons 2D, 3D and 4D. As soon as any one of the master relays is operated by energizing its operating winding, a holding circuit is completed which is effective to maintain the master relay in the operated position even though the corresponding call button is no longer depressed. Once the call, which is registered by the operation of a master relay, has been assigned to a particular car, the energizing circuit for the operating winding of the master relay is opened and it cannot again be closed until the call has been answered. It is, therefore, not possible to re-register a call until after the original call has been cancelled. There is no likelihood then that the call will be assigned to more than one car, and, therefore, the hall lantern which is illuminated definitely indicates the car which will stop in response to the registered call.

Referring now to Fig. 3 of the drawings, it will be observed that up floor relays ZUR, 3UR and 4UR are provided corresponding to the updirection of travel while down floor relays ZDR, 3DR and 4DR are provided corresponding to down direction of travel. Each of the floor relays is provided with a main operating winding and a resetting or cancelling winding. The resetting or cancelling winding is indicated by the reference character for the relay primed. Thus, the cancelling winding for floor relay 4UR is denominated 4UR. When a floor relay is energized, a holding circuit is completed for maintaining it in the operated position until the canceiling winding is energized to counteract the main winding and permit the relay to move to the non-operated position.

The energizing circuits to the main operating windings of the floor relays are controlled by means of an upzoning relay UT and a down zoning relay D1. The up zoning relay UT is arranged to be energized when the car A is at the lower terminal while the down zoning relay DT is arranged to be energized when the car A is at the upper terminal.

As set forth hereinbefore, the motor M may be controlled by any suitable control system. As illustrated, the motor M is provided with a main field winding MF, which may be connected between conductors Li and L2 which may be energized from any suitable source of direct current. The armature of the motor M is directly connected across the terminals of the armature of a generator G through a series field winding S, in order to provide what is commonly known as the Ward-Leonard system of control.

The generator G is provided with a main field winding GF, which may be controlled by means of a down reversing switch D and an up reversing switch U. When it is desired to move the car A downwardly, reversing switch D is operated to energize the generator field winding GF in such manner as to cause a voltage to be generated and applied to the armature of the motor M, so that it may be rotated to move the car in the desired direction. In like manner, if it is desired to move the car upwardly, reversing switch U is operated to energize the generator field winding GP in a reverse direction, thereby reversing the polarity of the voltage applied to the armature of the motor M and causing the car to move upwardly.

On operation of either of the reversing switches D or U, a control relay CR is also operated which is disposed to effect certain operating sequences including the cancelling of calls and extinguishing of the hall lanterns after a call has been answered.

In order to operate the car at a high speed, a resistor R is connected in series circuit relation with the generator field winding GF. A high speed switch V is provided for shunting out the resistor R, so that maximum excitation may be applied to the generator G with a corresponding increase in the speed of the elevator car A.

A stopping relay T is provided which is arranged to be energized when the car approaches a floor where a call has been registered and assigned to it. The stopping relay T is energized only so long as the call pick-up brush is in engagement with a segment, and, therefore, a holding relay HR is provided for completing the slow down sequence in response to the momentary operation of the stopping relay T.

In describing in detail the operation of my invention, it will be assumed that there is no car 5 present at the lower terminal and that car A is approaching it and is the next car to leave the lower terminal. t will also be assumed that the call button 3U on the third floor has been operated.

In response to the operation of the call button a circuit is completed for effecting the energization of the operating winding of the master relay Ll, 3U, EUM, 3UR3, BSURS, C3UR3, L2

A holding circuit is then completed for maintaining the master relay 3111M in the operated positon on the ciosure or contact members 3UM3. It will be observed that these contact members are connected in shunt circuit relation with the terminals oi the call button 3U. Therefore, the master re ay SUM will be maintained in the operated pos ion even though the call button 3U is no longer depressed.

As soon as car A arrives at the bottom tor-"ninal, up zoning relay UT is energized, since brush ii is in engagement with auxiliary floor segment ll Li, i i2, UT, BUTQ, CUTl, L2

The n of up zoning relay UT opens contact members UT l which are in series circuit relation with the operating winding of the corresponding up zoning relay BUT for car B. Thus, if car arrives at the lower terr al before car A leaves its up zoning relay BUT will not be energized. Therefore, no calls can be assigned to while car A is at the terminal, and its up zoning relay been operated.

As soon as the up zoning relay UT is energized, a circuit is completed for energizing the operating winding of up floor relay BUR;

La, scan, UTE, son, L2

*5 It will be recalled that up master relay 3UM is 'l energized, and, therefore, contact members are closed. As soon as up floor relay EUR is energized, an obvious holding circuit therefor is completed by the closure of contact members 1e operation or up floor relay 3UR opens conniemb r which are in series circuit the operating winding of the up master relay SUM. As a result, its winding is ded and it is not possible to reenergize it up floor relay 3UR is in the non-oper- It will then be understood that the call button EU is subsequently it will have no effect, since the energiz- '-'crit for the operating winding of the up relay SUM is opened.

The hall lantern ZUL corresponding to elevator car A on the third floor, and up direction is ill'uh inated:

Ll, SUL, 3UR2, L2

the up position. The up reversing switch U and control relay CR are then operated:

Ll, MS, Fl, U, CR, door interlocks L2 A circuit is also completed for energizing the generator field winding GF, to start the car:

Li, Ul, GF, U3, R, L2

The high speed switch V is operated by closure of contacts U5, to short circuit the resistor R and apply full voltage to the generator field winding GF:

The elevator car A is now moving upwardly in the shaft at full speed. It will continue at this speed unt l it is caused to slow down and stop at the t d. floor, in order to answer the call which has )een registered from that floor. On leaving th lower terminal, the energizing circuit for th operating winding of up zoning reley UT is o e d, and it is returned to the nonon. The next car, car B for ing at the lower terminal, will then ned to it all calls which are subsev stercd before it leaves the lower ter- Since e up zoning relay UT is in the .sition, it is not possible for any rev ir ered on any of the up ed with car A. Therefore,

, will have to answer is that call which is registered from the third floor.

As car A approaches the third floor, call pickup hr :11 XU first engages call pick-up floor segment 35. A circuit is then completed for energizing the stopping relay T for as long as the brush XU is in engagement with the segment 35:

though the stopping relay T no longer remains energized:

o erated p Ll, Tl, HR, CRl, L2 At contact members l-lRi, an obvious holding circuit for the holding relay HR is completed.

As soon as the stopping ay T is energized, a circuit is also completed for energizing the op- 5 crating winding of the slow down inductor switch E wh ch is connected in parallel c' cult relation the operating winding of the holding relay However, contact members El or the slow Lit. down inductor switch E are not opened until they come into proximity to the inductor plate EU.

The contact inc sbers El are opened as soon as car A, in its movement upwardly in the shaft, causes t m. to pass the inductor plate EU. The energiz 1g circuit for he opeating winding of the high speed switch V is opened and this switch is moved to the non-operated position. Contact members V l are then opened, inserting the resister It in series circuit relation with the generator field winding The elevator car is then cc rrespon ingly slowed down in order to approach r at the proper landing speed.

'gization of the high speed switch V cause cont .ct members V2 to be closed, thereby completing a circuit for eliecting energization of the operating winding of the stopping inductor switch F:

Ll, HRI, V2, F, CRI, L2

As soon as contact members F I are moved into proximity with the inductor plate FU by the continued upward movement of car A, they are opened and the previously traced energizing circuit for the up reversing switch U and the control relay OR is opened. As a result, the generator field winding GF is deenergized, the brake 4 is applied and the car A is stopped at the level of the third floor.

It will be observed that the call cancelling brush YU will be in engagement with the call cancelling floor segment 33 when the car is stopped at the third floor. No operation, however, can take place as a result of this connection, since the control relay CR is in the non-operated position, although it in opening has deenergized the operating winding of the holding relay HR, as well as the operating windings of the inductor switches E and F.

However, as soon as the operator moves the master switch MS to the up position, the control relay CR is again energized, as set forth hereinbefore, and contact members CR2 are closed. The cancelling winding 3UR is then energized:

Ll, 3URI, 3UR, 33, YU, HRZ, CR2, L2

The up floor relay 3UR is then returned to the non-operated position. As a result of this operation of the up floor relay 3UR, the energizing circuit for the hall lantern 3UL is opened and it is extinguished. At the same time at contact members 3UR3, the circuit to the operating winding of the up master relay 3UM, is again completed to conductor L2, so that it may be energized on a subsequent operation of the call button 3U.

The remaining portion of the operating sequence for starting the car from the third floor will be the same as described hereinbefore, in connection with starting it from the bottom terminal. Therefore, it will not be repeated.

It will be understood that the functioning of the system will be similar, assuming that car A is the next car to leave the top terminal, in order to answer calls in the down direction which have been assigned to it. It will also be understood that the functioning of the system associated with car B will be identical with that described hereinbefore in connection with car A.

It will be obvious that the car may be stopped at any floor by centering the master switch MS. A circuit is thus completed in parallel with contact members TI and the stopping sequence is then identical with that described hereinbefore when the stopping relay T is operated. It will be understood that any suitable control system may be provided for presetting calls within the cars which will render it unnecessary to provide the stop position for the master switch MS. Since such systems are well known and form no part of my invention, a detailed illustration and description thereof are omitted.

Since certain further changes may be made in the above construction and different embodiments of the invention may be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and. not in a limiting sense.

I claim as my invention:

1. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, call means individual to each floor, and means responsive to the operation of said call means for assigning the call only to the next car to leave a terminal.

2. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, call registering means at each door for each direction of travel, and means responsive to the operation of said call registering means for assigning the call only to the next car to leave a terminal in the direction for which the call is registered.

3. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, call means individual to each floor, means responsive to the operation of said call means for assigning the call only to the next car to leave a terminal, and means for indicating at the floor the car to which the call has been assigned.

4. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, call registering means at each floor for each direction of travel, means responsive to the operation of said call registering means for assigning the call only to the next car to leave a terminal in the direction for which the call is registered, and means for indicating at the floor the car to Which the call has been assigned in the direction for which the call is registered.

5. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, call means for each floor, means individual to each car for responding to said call means to effect the stopping of the car, and means for limiting the response of said last named means to the calls originated before a car leaves a terminal.

6. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, call registering means at each floor for each direction of travel, means individual to each car for stopping it in response to the registration of a call, and means for limiting the number of calls to which said last named means shall respond to those registered before a car leaves a terminal in the direction for which the call is registered.

7. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, call means for each floor, means individual to each car for responding to said call means to eiiect the stopping of the car, means for limiting the response of said last named means to the calls originated before a car leaves a terminal, and means for indicating the car which will respond to a call at the floor where the call originated.

8. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, call registering means at each floor for each direction of travel, means individual to each car for stopping it in response to the registration of a call, means for limiting the number of calls to which said last named means shall respond to those registered before a car leaves a terminal in the direction for which the call is registered, and means for indicating the car which will respond to a call at the floor where the call is registered in the direction for which the call is registered.

9. In a system for operating a plurality of elevator cars between upper and lower. terminals past a plurality of floors, in combination, call registering means for each floor for each direction of travel, means individual to each floor and to each car for eifecting the stopping thereof in response to the registration of a call, and means for limiting the number of calls erlective for stopping any car to those registered before said car leaves a terminal in the direction for which the calls are registered.

10. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, call registering means for each floor for each direction of travel, means individual to each fioor and to each car for effecting the stopping thereof in response to the registration of a call, and means for assigning all of the registered calls to the next car to leave a terminal in the direction for which the calls are registered only when the car is at the terminal.

11. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, call registering means for each floor for each direction of travel, means individual to each floor and to each car for effecting the stopping thereof in response to the registration of a call, means for limiting the number of calls effective for stopping any car to those registered before said car leaves a terminal in the direction for which the calls are registered, and a hall lantern individual to each floor, to each car, and to each direction of travel for indicating the car which will respond to a call at the floor where the call is registered in the direction for which the call is registered.

12. In a system for operating an elevator car between upper and lower terminals past a plurality of floors, in combination, call means for each floor, means individual to each floor for effecting the stopping of the car in response to the operation of the call means individual thereto, and means for limiting the number of calls efiective for stopping the car to those initiated before the car leaves a terminal.

13. In a system for operating an elevator car between upper and lower terminals past a plurality of floors, in combination, call means for each floor, means individual to each floor for effecting the stopping of the car in response to the operation of the call means individual thereto, means for limiting the number of calls eifective for stopping the car to those initiated before the car leaves a terminal, and means for indicating the car which will respond to a call at the floor where the call originated.

14. In a system for operating an elevator car between upper and lower terminals past a plurality of floors, in combination, call registering means for each floor for each direction of travel, means individual to each floor for effecting the stopping of the car at a floor in response to the registration of a call from that floor, and means for limiting the number of calls effective for stopping the car to those registered before it leaves a terminal in the direction for which the calls are registered.

15. In a system for operating an elevator car between upper and lower terminals past a plurality of floors, in combination, call registering means for each floor for each direction of travel,

means individual to each fioor for effecting the stopping of the car at a floor in response to the registration of a call from that floor, means for limiting the number of calls effective for stopping the car to those registered before it leaves a terminal in the direction for which the calls are registered, and means disposed to be operated on operation of said second named means for indicating the car which will respond to a call at the floor where the call is registered in the direction for which it is registered.

16. In a system for operating an elevator car between upper and lower terminals past a plurality of floors, in combination, call means for each of said floors, means comprising a relay for each of said call means disposed to respond to the operation of a corresponding call means, and means disposed to limit the number or" call means to which said second named means shall respond to those operated before the car leaves a terminal.

17. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, a call button at each floor for registering calls for each direction of travel, a relay individual to each call button and disposed to be operated thereby, means individual to each floor and to each car I for effecting the stopping thereof in response to the operation of a relay, and means for limiting the number of relays to which said last named means shall be responsive to effect the stopping of a car to those relays operated before the car leaves a terminal in the direction for which the calls are registered.

18. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, a call button at each floor for registering calls for each direction or travel, a relay individual to each call button and disposed to be operated thereby, means individual to each floor and to each car for effecting the stopping thereof in response to the operation of a relay, means for limiting the number of relays to which said last named means shall be responsive to effect the stopping of a car to those relays operated before the car leaves a terminal in the direction for which the calls are registered; a hall lantern individual to each floor, to each car, and to each direction of travel and energizable in response to the operation or" said first named means for indicating the car which will respond to a call at the floor where the call is registered; and means for effecting the deenergization of an energized hall lantern when the car leaves the floor individual thereto after stopping in response to a call at the floor.

19. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, a call button at each floor for each direction of travel, a relay individual to each call button and disposed to be operated thereby for registering a call, means for assigning the registered call to the next car to leave a terminal in the direction for which the call is registered, and means for maintaining the relays in non-registering condition until the call is cancelled by the stopping of a car at the floor in response to the registration of a call.

20. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, a call button at each floor for each direction of travel,

a relay individual to each call button and disposed to be operated thereby for registering a call, means for limiting the number of calls assigned to the next car to leave a terminal in the direction for which the calls are registered to those registered before the car leaves the terminal, and means for preventing the re-registration of a call until the registered call is cancelled by the stopping of the car at the floor in response to the registration of the call.

21. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, call registering means for each floor for each direction of travel, means for assigning registered calls to the next car to leave a terminal in the direction for which the calls are registered, and means for preventing the re-registration of a call until the registered call is cancelled by the stopping of a car in response to the registration of a call at the floor where the call is registered.

22. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, call registering means for each floor for each direction of travel, means for limiting the number of calls ned to the next car to leave a terminal in the direction for which the calls are registered to those registered before the car leaves the terminal, and means for preventing the re-registration of a call until the registered call is cancelled by the stopping of a car in response to the registration of a call at the floor where call is registered.

23. In a system for operating a plurality of elevator cars between upper and lower terminals past a, plurality of floors, in combination, up and down call buttons at each floor, a master relay individual to each call button and disposed to be energized thereby for registering a call and maintaining the call registered until it is cancelled, up and down floor relays individual to each floor and to each car and operable in response to the operation of a corresponding master relay; said floor relays disposed when operated to efiect the stopping of the car individual thereto on arriving at a, floor where a call is registered, to effect the deenergization of the corresponding master relay to cancel the call, and to prevent the reenergization of the master relay until the call has been answered; and means for limiting the number of master relays to which said floor relays shall be responsive to the number of master relays operated before the car leaves a terminal in the direction for which the calls are registered.

24. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, up and down call buttons at each floor, a master relay individual to each call button and disposed to beenergized thereby for registering a call and maintaining the call registered until it is cancelled, up and down floor relays individual to each floor and to each car and operable in response to the operation of a corresponding master relay; said floor relays disposed when operated to effect the stopping of the car individual thereto on arriving at a floor where a call is registered, to effect the deenergization of the corresponding master relay to cancel the call, and to prevent the reenergization of the master relay until the call has been answered; and a zoning relay individual to each terminal and to each car and disposed to be energized when the car individual thereto arrives at a terminal, said zoning relay on being energized disposed to prevent the energization of the remaining zoning relays at its terminal and to eifect the energization of the floor relays individual to its car corresponding to the master relays that have been energized by the operation of the corresponding call buttons.

25. In a system for operating a plurality of elevator cars between upper and lower terminals past a plurality of floors, in combination, up and down call buttons at each floor, a master relay individual to each call button and disposed to be energized thereby for registering a call and maintaining the call registered until it is cancelled, up and down hall lanterns individual to each car at each floor, up and down floor relays individual to each floor and to each car and operable in response to the operation of a corresponding master relay; said floor relays disposed when operated to effect the stopping of the car individual thereto on arriving at a floor where a call is registered, to effect the deenergization of the corresponding master relay to cancel the call, to prevent the reenergization of the master relay until the call has been answered, and to effect the energization of the corresponding hall lantern; and means for limiting the number of master relays to which said floor relays shall be responsive to the number of master relays operated before the car leaves a terminal in the direction for which the calls are registered.

HAROLD W. WILLIAMS. 

